J/AJ/142/140 Optical spectroscopy of ρ Oph stars. II. (Erickson+, 2011)
The initial mass function and disk frequency of the ρ Ophiuchi cloud:
an extinction-limited sample.
Erickson K.L., Wilking B.A., Meyer M.R., Robinson J.G., Stephenson L.N.
<Astron. J., 142, 140 (2011)>
=2011AJ....142..140E 2011AJ....142..140E
ADC_Keywords: Clusters, open ; Stars, pre-main sequence ; Equivalent widths ;
MK spectral classification
Keywords: ISM: individual objects (rho Ophiuchi cloud) -
open clusters and associations: individual (Upper Scorpius) -
stars: formation - stars: pre-main sequence
Abstract:
We have completed an optical spectroscopic survey of an unbiased,
extinction-limited sample of candidate young stars covering 1.3deg2
of the ρ Ophiuchi star-forming region. While infrared, X-ray, and
optical surveys of the cloud have identified many young stellar
objects (YSOs), these surveys are biased toward particular stages of
stellar evolution and are not optimal for studies of the disk
frequency and initial mass function. We have obtained over 300 optical
spectra to help identify 135 association members based on the presence
of Hα in emission, lithium absorption, X-ray emission, a
mid-infrared excess, a common proper motion, reflection nebulosity,
and/or extinction considerations.
Description:
Over 200 moderate resolution spectra were obtained for 184 stars
identified through R- and I-band photometry as candidate YSOs.
Fifty-two of these stars had spectral classifications reported in
Paper I (Wilking et al., Cat. J/AJ/130/1733), allowing us to refine
our previous spectral classifications. Newly observed YSO candidates
numbered 133. These observations are described in detail in the
following sections.
Optical spectra were obtained for stars located over a 1.3deg2 area
centered on L1688 using Hydra, the multi-fiber spectrograph, on two
different telescopes. The first set of observations were made using
Hydra on the Blanco 4m telescope at Cerro Tololo Inter-American
Observatory on 2003 August 10-12. The second set of observations
utilized Hydra on the WIYN6 3.5m telescope on 2006 June 15-17.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 156 219 Optical properties of candidate young stellar objects
table3.dat 113 135 Association members with optical spectra
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See also:
J/ApJ/438/813 : Stellar population in ρ Oph cloud core (Strom+, 1995)
J/ApJS/112/109 : Rho Oph Near-IR Positions and Photometry (Barsony+, 1997)
J/A+A/359/113 : X-ray and IR study of Rho Oph dark cloud (Grosso+, 2000)
J/ApJ/613/393 : X-ray and radio sources in ρ Oph Core A (Gagne+, 2004)
J/A+A/429/963 : XMM-Newton observation of the rho Oph cloud (Ozawa+, 2005)
J/ApJ/630/381 : Mid-IR imaging in ρ Oph (Barsony+, 2005)
J/A+A/447/609 : 1.2mm continuum observations in rho Oph cloud (Stanke+, 2006)
J/A+A/452/245 : Near-IR photometry of PMS stars in rho Oph (Natta+, 2006)
J/ApJ/671/1800 : SCUBA observations of ρ Oph cloud (Andrews+, 2007)
J/A+A/485/155 : HK photometry of rho Oph PMS stars (Alves de Oliveira+, 2008)
J/A+A/510/A98 : 12C18O(3-2) map of rho Oph A (Liseau+, 2010)
J/A+A/515/A75 : ρ Oph cloud low-mass population (Alves de Oliveira+, 2010)
J/A+A/519/A34 : YSOs in DROXO (Deep rho Oph XMM obs.) (Pillitteri+, 2010)
J/ApJ/719/550 : Deep NIR imaging of ρ Oph cloud core (Marsh+, 2010)
J/ApJ/751/22 : Candidates of the ρ Oph cluster (Barsony+, 2012)
J/AJ/130/1733 : Optical spectroscopy of ρ Oph stars (Wilking+, 2005)
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 A4 --- ID HYDRA field and aperture number of
observation (N-NN), DIFFERS from PAPER I
(Wilking et al. 2005, Cat. J/AJ/130/1733)
6- 29 A24 --- Name Sources names from optical or infrared
studies (1)
31- 51 A21 --- XName X-ray source association (2)
53- 54 I2 h RAh Right ascension (J2000)
56- 57 I2 min RAm Right ascension (J2000)
59- 62 F4.1 s RAs Right ascension (J2000)
64 A1 --- DE- Declination sign (J2000)
65- 66 I2 deg DEd Declination (J2000)
68- 69 I2 arcmin DEm Declination (J2000)
71- 72 I2 arcsec DEs Declination (J2000)
74- 77 A4 --- Li? [Yes: ] Li detection? (Yes or Yes:)
79 A1 --- l_EWHa Limit flag on EWHa
80- 86 F7.2 0.1nm EWHa ?=- Hα equivalent width
87- 89 A3 --- n_EWHa uncertain value (:) or emission (+em)
92- 96 F5.2 mag Icmag ?=- Cousins I magnitude (3)
99-102 F4.2 mag Rc-Ic ?=- Cousins R-I colour index (3)
104-121 A18 --- SpType1 Previous spectral type with references (4)
123-135 A13 --- SpType2 Spectral type
137-144 A8 --- SpType Adopted spectral type
146-156 A11 --- Notes "Giant" or "Poss. dwarf" star
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Note (1): Sources names from optical or infrared studies by:
* (GSS, Source 2) Grasdalen et al. 1973ApJ...184L..53G 1973ApJ...184L..53G
* (VSSG) Vrba et al. 1975ApJ...197...77V 1975ApJ...197...77V
* (VSS) Vrba et al. 1976AJ.....81..958V 1976AJ.....81..958V
* (WSB) Wilking et al. 1987AJ.....94..106W 1987AJ.....94..106W
* (WLY) Wilking et al. 1989ApJ...340..823W 1989ApJ...340..823W
* (GY) Greene & Young 1992ApJ...395..516G 1992ApJ...395..516G
* (ISO-Oph) Bontemps et al. 2001A&A...372..173B 2001A&A...372..173B
* (AOC) Alves de Oliveira & Casali 2008A&A...485..155A 2008A&A...485..155A
* (UCAC3) Zacharias et al. 2009, Cat. I/315
Note (2): X-ray source association from
* the EINSTEIN survey by (ROX) Montmerle et al., 1983ApJ...269..182M 1983ApJ...269..182M,
* the ROSAT surveys by (RXJ) Martin et al., 1998MNRAS.300..733M 1998MNRAS.300..733M and
* (ROXRF) Grosso et al., 2000A&A...359..113G 2000A&A...359..113G,
* the Chandra surveys by ([IKT2001]) Imanishi et al., 2001ApJ...557..747I 2001ApJ...557..747I and
* (ROXC) N. Grosso 2005, private communication, or the XMM-Newton survey by
* (ROXN) Ozawa et al., 2005A&A...429..963O 2005A&A...429..963O.
Note (3): R- and I-band photometry from this study except for ROX 3 which are
from S. Gordon & K.M. Strom 1990, unpublished data.
Note (4): References for spectral types:
(BA) = Bouvier & Appenzeller, 1992A&AS...92..481B 1992A&AS...92..481B
(MMGC) = Martin et al., 1998MNRAS.300..733M 1998MNRAS.300..733M
(LR) = Luhman & Rieke, 1999ApJ...525..440L 1999ApJ...525..440L
(WMR) = Wilking et al., 2005AJ....130.1733W 2005AJ....130.1733W
(G) = Geers et al., 2007A&A...476..279G 2007A&A...476..279G
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Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 A4 --- ID HYDRA field and aperture number of
observation (N-NN), NOT AS IN PAPER I
6- 26 A21 --- Name Sources names from optical or infrared
studies (1)
28- 31 A4 --- Source Name from Wilking et al. (2005, J/AJ/130/1733),
N-NN
33- 37 A5 --- SpType Optical spectral types from this study or
Wilking et al. (2005, J/AJ/130/1733)
except noted
39- 45 A7 --- r_SpType Reference for spectral type (2)
47- 50 F4.1 mag AV Absorption in V band
52- 55 A4 --- r_AV Reference for AV (3)
58- 62 F5.2 mag IMAG Absolute I-band magnitude
64- 68 F5.3 [K] logTe Effective temperature
70- 74 F5.2 [Lsun] logL Luminosity
76- 79 F4.2 Msun Mass ?=- Stellar mass (4)
81 A1 --- l_logAge Limit flag on logAge
82- 85 F4.2 [yr] logAge ?=- Age
86- 90 A5 --- n_logAge Note on logAge
92-109 A18 --- Crit Criteria for young stellar association (5)
111-113 A3 --- Notes ? Pecularities of the source (6)
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Note (1): Sources names from optical or infrared studies noted in Table 2 plus:
(SR) = Struve & Rudkjobing, 1949ApJ...109...92S 1949ApJ...109...92S
(DoAr) = Dolidze & Arakelyan, 1959AZh....36..444D 1959AZh....36..444D
(EL) = Elias, 1978ApJ...224..453E 1978ApJ...224..453E
(Chini) = Chini, 1981A&A....99..346C 1981A&A....99..346C
(WL) = Wilking & Lada, 1983ApJ...274..698W 1983ApJ...274..698W
(ROXR1) = Casanova et al., 1995ApJ...439..752C 1995ApJ...439..752C
Note (2): Optical spectral types references as follows:
(EL) = Elias, 1978ApJ...224..453E 1978ApJ...224..453E
(CK) = Cohen & Kuhi, 1979ApJS...41..743C 1979ApJS...41..743C
(HS) = Houk & Smith-Moore 1988, Vol. 4 Cat. III/133
(GS) = S. Gordon & K. M. Strom 1990, private communication
(BA) = Bouvier & Appenzeller, 1992A&AS...92..481B 1992A&AS...92..481B
(TQ) = Torres et al., 2006A&A...460..695T 2006A&A...460..695T
(MMGC) = Martin et al., 1998MNRAS.300..733M 1998MNRAS.300..733M
Note (3): R- and I-band magnitudes used to compute AV and Lbol are from this
study except where noted, as follows:
(C) = Chini 1981A&A....99..346C 1981A&A....99..346C
(GS) = S. Gordon & K. M. Strom 1990, private communication
(BA) = Bouvier & Appenzeller 1992A&AS...92..481B 1992A&AS...92..481B
(W) = Walter et al. 1994AJ....107..692W 1994AJ....107..692W
(2M) = denotes J- and H-band data from 2MASS were used to compute AV
and Lbol and M(J) replaces M(I) in Column IMAG.
Note (4): Masses and ages estimated from the tracks and isochrones of
D'Antona & Mazzitelli 1997MmSAI..68..807D 1997MmSAI..68..807D and F. D'Antona & I.
Mazzitelli 1998, private communication except where noted in the last column.
Note (5): Association membership established through
* location above the main sequence and AV>1.5 mag (ext),
* the presence of Hα emission EW>10Å(ha),
* an infrared excess (IRX),
* lithium absorption (li),
* proper motion (pm),
* reflection nebulosity (ref. neb.),
* near-infrared variability (var), or
* X-ray emission (x).
Note (6): Notes as follows:
1 = sits below main sequence, possible foreground star
2 = spectroscopic binary Casassus et al., 2008MNRAS.391.1075C 2008MNRAS.391.1075C
3 = mass and age derived from the tracks and isochrones of
Palla & Stahler, 1999ApJ...525..772P 1999ApJ...525..772P
4 = subarcsecond companion observed in infrared and treated as a single
object (Barsony et al. 2003ApJ...591.1064B 2003ApJ...591.1064B; Prato 2007ApJ...657..338P 2007ApJ...657..338P)
5 = discordant proper motion (Mamajek 2008AN....329...10M 2008AN....329...10M)
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History:
From electronic version of the journal
References:
Wilking et al., Paper I 2005AJ....130.1733W 2005AJ....130.1733W, Cat. J/AJ/130/1733
(End) Patricia Vannier [CDS] 18-Jan-2013